This project explores the applicability of expert system technology to the National Aerospace Plane (NASP). It will investigate the feasibility of developing real-time cooperating, distributed expert systems executing in either on-board or ground based computers (or both) to perform a variety of functions. The functions include mission planning (including real-time replanning); system monitoring, diagnostics and management; and trajectory management and control. Prudent application of this branch of artificial intelligence to NASP will improve the platform's operational versatility, adaptability, and effectiveness. Specific potential improvements include an on-board capability of adjusting a mission plan in real-time in response to a system failure or degraded performance, an on-board capability of monitoring and providing diagnostics for NASP subsystems, and preflight planning passed on the automated flight test management system. Expert system technology is particularly suited to abort trajectory management, propulsion system monitoring and diagnostics, and flight test planning.Extensions of this work could apply to planet surface and atmospheric explorers (such as the Mars Rover), military reconnaissance vehicles, and others.expert systems, planners, monitoring, diagnostics, trajectorySTATUS: Phase I Only